Dominant and Recessive Genes

As I mentioned in my last blog I will now attempt to describe and help my readers to better understand how dominant and recessive genes work. This explanation comes from my own understanding of dominant and recessive genes, as described to me by my grade 12 biology teacher.

Every cell in our body contains a nucleus (or centre), where the instructions for our genetic makeup are held. These instructions come in the form of our genes. When we are concieved we recieve one gene from each of our parents for each specific trait we will have, in order to determine what types of traits we will have. Our parents carry two different genes for each of the specific traits that we will recieve. They can carry either a combination of Dominant/Ressessive, Dominant/Dominant, or Recessive/Recessive pairs of genes for any given trait in themselves. Our traits are dependant upon which of these two genes are passed on to us by our parents. The combinations of these genes can determine anything including our facial features, hair colour, height, and even wether or not we will inherit an illness. When attempting to understand inheritance you must also be aware of the fact that if a parent were to pass onto you a dominant gene you would recieve whatever trait they have passed on, regardless of if the other parent has passed onto you a dominant or recessive gene for that trait. This is because dominant genes always overpower recessive genes. The only possible way for someone to aquire a recessive trait is to have both parents pass on a recessive gene for that trait.


To explain this even further, I will give you a simple example of how dominant and recessive genes are able to appear in a child. This example comes from a diagram that I found on the following website: http://library.thinkquest.org/C0123260/basic%20knowledge/dominant%20and%20recessive.htm.




The Capital "N's and D's" in this diagram are used to represent a dominant gene while the lowercase "n's and d's" are used to represent a recessive gene. As you can see the mother and father are represented in each diagram. In the first diagram it is shown how it is possible for one to inherit two recessive genes. It shows that in order to inherit a recessive trait one would have to recieve a recessive gene from both their mother and father in order to aquire that trait. In the second diagram it is shown how it is possible for one to inherit a dominant trait even if one parent is only able to pass on recessive traits. If the parent with the one dominant trait passes on that trait it is inevitable that that dominant trait will show in the offspring no matter what gene the other parent passes on.

I hope I have done an acceptable job at explaining this process. This will come in handy when in my next blog I discuss how changing our genes could be beneficial to our health.